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Choosing and modifying components

16 min

Skills you'll build4 skills
  • Match cryoprecipitate, plasma, or another component to the factors that need replacing
  • Select plasma without donor antibodies against the recipient's red cells
  • Choose leukoreduction, irradiation, or washing for the risk each one reduces
  • Check a red-cell request against the hemoglobin threshold for the patient's setting

At the bench: Check component identity, storage, and suitability before issue

Try first

Try first

A patient with cirrhosis is bleeding before a procedure. The INR is 2.6, the APTT is 58 s, the fibrinogen is 240 mg/dL and the platelet count is 110 × 10³/µL. Which component replaces what is missing?

Keep going to see the reasoning.

Keep going to see the reasoning.

Right. Keep going to follow the reasoning.

Keep going to see the reasoning.

Get the idea

Use the explanation to check your first decision.

Match the component to the deficit

Each component replaces something specific:1

ComponentReplacesLaboratory indication
Red cellsOxygen-carrying capacityHemoglobin below the threshold for the setting
PlateletsPlateletsA low count with bleeding, or below a prophylaxis threshold
PlasmaThe coagulation factors togetherRaised INR and APTT with bleeding
CryoprecipitateFibrinogen, factor VIII, factor XIII, von Willebrand factorLow fibrinogen with bleeding

Cryoprecipitate is used mainly to replace fibrinogen. Factor concentrates are preferred for hemophilia A, von Willebrand disease and factor XIII deficiency. An INR of 1.7 or less reflects enough factor activity for hemostasis, and plasma given to correct it is a relative contraindication.1

ABO compatibility for plasma

Plasma contains the donor's anti-A and anti-B. It must be ABO-compatible with the recipient's red cells. Group AB plasma has neither antibody and can be given to a recipient of any group. Group O plasma has both and can be given only to group O recipients. The D type of plasma does not need to match.1

Component modifications

  1. Leukoreduction removes most donor leukocytes. It reduces febrile reactions, HLA alloimmunization and cytomegalovirus transmission.
  2. Irradiation stops donor T lymphocytes from dividing and prevents transfusion-associated graft-versus-host disease. The T lymphocytes that leukoreduction leaves behind are still viable, so leukoreduction does not replace irradiation.
  3. Washing removes plasma proteins. It is used for patients with recurrent severe allergic reactions and for IgA-deficient patients with anti-IgA.

Irradiation indications include intrauterine transfusion, cellular components from blood relatives, HLA-selected components, hematopoietic progenitor cell transplant recipients and purine analogue therapy such as fludarabine.1

Red cell transfusion thresholds

For most stable hospitalized adults, the 2023 AABB guideline recommends considering red cells when hemoglobin is below 7 g/dL.2 After acute myocardial infarction, a 2025 AABB guideline suggests a liberal strategy, with transfusion below 10 g/dL.3 The transfusion service reviews each request against the patient's setting, and the treating clinician makes the transfusion decision.4

Follow the bench demonstration

Sources for this step
References
  1. Association for the Advancement of Blood & Biotherapies, American Red Cross, America's Blood Centers, Armed Services Blood Program. Circular of Information for the Use of Human Blood and Blood Components. June 2024. Accessed September 27, 2026.
  2. Carson JL, Stanworth SJ, Guyatt G, et al. Red blood cell transfusion: 2023 AABB international guidelines. JAMA. 2023;330(19):1892-1902. doi:10.1001/jama.2023.12914
  3. Pagano MB, Stanworth SJ, Dennis J, et al. Red cell transfusion in acute myocardial infarction: AABB international clinical practice guidelines. Ann Intern Med. 2025;178(10):1469-1477. doi:10.7326/ANNALS-25-00706
  4. Bloch EM, Campbell-Lee S, McKenna DH Jr, Montemayor-Garcia C, Schwartz J, Shaz B, Storry J, eds. Technical Manual. 22nd ed. AABB; 2026.

Watch one

Read each decision and its explanation.

Tomás Long, 58, MRN 6627405, is group B, D-negative. He needs 4 units of plasma before a procedure. The freezer holds group O, A, B and AB plasma, some from D-positive donors.

Which plasma can he receive?

  1. Start from his red cells. Group B cells carry the B antigen.

    Plasma compatibility depends on whether the donor's ABO antibodies react with the recipient's red cells.

  2. Set aside group O plasma. Its anti-B would bind his red cells.

    Group O plasma contains both anti-A and anti-B.

  3. Set aside group A plasma for the same reason.

    Group A plasma contains anti-B.

  4. Keep group B plasma, which has anti-A only, and group AB plasma, which has neither antibody.

    Neither group B nor group AB plasma contains anti-B.

  5. Accept any D type.

    Plasma does not need to be D-matched.

Group B or group AB plasma, from D-positive or D-negative donors.

Practice this skill

Your turn

Problem 1 of 3 · Hints available

Which set lists proteins concentrated in cryoprecipitate?

Correct. Cryoprecipitate is the cold-insoluble part of thawed plasma, so it concentrates fibrinogen, factor VIII, factor XIII, and von Willebrand factor. Its main use today is fibrinogen replacement.

Incorrect. This is the vitamin K-dependent factor set associated with four-factor prothrombin complex concentrates.

Incorrect. Those plasma proteins are supplied as separate derivatives. They are not the defining hemostatic contents of cryoprecipitate.

Hint
  1. Cryoprecipitate is the protein fraction that stays insoluble when frozen plasma thaws in the cold.
  2. Ask which proteins stay insoluble in the cold and are used mainly to replace fibrinogen.

Review Plasma and cryoprecipitate

Problem 2 of 3 · Hints available

Which component modification prevents donor T-lymphocyte proliferation to reduce transfusion-associated graft-versus-host disease?

Incorrect. Washing primarily removes residual plasma proteins. It does not reliably prevent donor T-cell proliferation.

Correct. Irradiation damages donor lymphocyte DNA, so surviving T cells cannot divide and attack the recipient.

Incorrect. Leukoreduction decreases donor leukocytes, but it does not replace irradiation for this indication.

Hint
  1. The disease needs donor T lymphocytes that can still divide.
  2. Leukoreduction leaves some lymphocytes in the unit.

Review Special processing requirements

Problem 3 of 3 · On your own

A group AB patient needs plasma. Which plasma is ABO-compatible?

Group O plasma contains both anti-A and anti-B. Both antibodies would bind this patient's A and B antigens.

Used the red-cell compatibility direction for plasma

Plasma contains the donor's anti-A and anti-B, so plasma ABO compatibility is the reverse of red-cell compatibility. Group O plasma has both antibodies and can hemolyze a group A recipient's red cells. Group AB plasma lacks both and is compatible with a recipient of any ABO group.

Group A plasma contains anti-B, which would bind the patient's B antigen.

Group B plasma contains anti-A, which would bind the patient's A antigen.

Group AB plasma has neither anti-A nor anti-B. It is the only plasma compatible with red cells that carry both antigens.

Review Plasma and cryoprecipitate

Use it

Read the case evidence, then make each decision. The step is complete without it.

  • Henryk Piper, 71, MRN 3981046, is admitted with an acute myocardial infarction.
  • He has chronic lymphocytic leukemia treated with fludarabine. His transfusion record requires irradiated cellular components.
  • His hemoglobin is 8.6 g/dL, and his cardiologist orders 1 red-cell unit.
  • The audit software flags the order because the hemoglobin is above 7 g/dL.
  • The group A units on the shelf are leukoreduced, and none is irradiated.
Decision 1 of 3

How does the transfusion service review the flagged order?

The 7 g/dL threshold is for most stable hospitalized adults. Acute myocardial infarction has its own guideline.

Applied the 7 g/dL threshold after myocardial infarction

Red-cell thresholds depend on the clinical setting. For most stable hospitalized adults the threshold is 7 g/dL, and after acute myocardial infarction the 2025 AABB guideline suggests a liberal strategy below 10 g/dL. Reviewing a request against the wrong setting's threshold flags an appropriate order or passes an inappropriate one. The transfusion decision rests with the treating clinician.

The guideline suggests a liberal strategy below 10 g/dL after acute myocardial infarction, and 8.6 g/dL is below that. The cardiologist makes the transfusion decision.

The transfusion service reviews the request against the setting and does not make the transfusion decision. Delaying issue would withhold red cells the guideline supports.

Review Red cell thresholds

Decision 2 of 3

Which unit is issued?

Fludarabine is a purine analogue, and his record requires irradiation. Irradiating a leukoreduced unit meets both requirements.

The T lymphocytes left after leukoreduction are still viable. Without irradiation they can cause transfusion-associated graft-versus-host disease.

Substituted leukoreduction for required irradiation

Leukoreduction lowers the leukocyte count, and the T lymphocytes that remain are still viable. Irradiation stops donor T cells from proliferating. A leukoreduced unit issued where irradiation is required can still cause transfusion-associated graft-versus-host disease.

Washing removes plasma proteins for allergic reactions and anti-IgA. It does not stop donor T lymphocytes from dividing.

Review Special processing requirements

Decision 3 of 3

Two days later he bleeds after a procedure. His fibrinogen is 85 mg/dL, his INR is 1.3 and his platelet count is 180 × 10³/µL. Which component replaces what is missing?

Plasma carries fibrinogen at plasma concentration, so raising a fibrinogen of 85 mg/dL would take a large volume. His INR of 1.3 shows the other factors are close to adequate.

A count of 180 × 10³/µL is not the cause of this bleeding.

Fibrinogen is the only deficit. Cryoprecipitate is a concentrated source of fibrinogen, and a posttransfusion fibrinogen shows the response.

Review Expected response per component

Each decision followed from the patient's setting. After acute myocardial infarction, a hemoglobin of 8.6 g/dL is within the guideline for transfusion. Fludarabine therapy requires irradiated cellular components, and an isolated low fibrinogen with bleeding pointed to cryoprecipitate.

For reference

Sources checked